1,347 research outputs found

    Agilidad, flexibilidad de producción e innovación en la empresa manufacturera española

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    Este artículo analiza en una muestra de empresas manufactureras españolas la relación de la producción ágil con el esfuerzo interno y la cooperación externa en innovación tecnológica. Los resultados del estudio indican que las empresas con mayor capacidad de agilidad utilizan con más intensidad un amplio conjunto de tecnologías agiles de desarrollo, fabricación y suministro. Las empresas más ágiles también cooperan externamente más en innovación y dicha cooperación modera la flexibilidad de producción de las empresas, indicando con ello que, gracias a la cooperación externa en innovación las empresas con menor flexibilidad de producción pueden aun así conseguir mayor capacidad de agilidad

    Criticalidade auto-organizada no cerrado? Invariância escalar dos padrões texturais e espectrais de fitosionomias do cerrado paulista.

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    Padrões presentes em uma paisagem podem estar associados importantes processos relativos à organização e dinâmica do sistema. Objetivo: O objetivo do presente trabalho foi avaliar, a partir de algumas métricas derivadas do paradigma da complexidade, a complexidade dos padrões texturais e espectrais de fisionomias do Cerrado paulista a fim de verificar quais propriedades relativas à sua organização e dinâmica tais padrões podem revelar. Metodologia: Para tanto, imagens do sensor Aster de três unidades de conservação do estado de São Paulo foram analisadas, utilizando-se dois tipos de medidas (dimensão fractal e medidas baseadas na entropia informacional) para avaliar a complexidade dos padrões texturais e espectrais das fisionomias. Resultados e discussão: Todas as fisionomias, nas três localidades estudadas e para todas as medidas usadas, apresentarem em diversas ocasiões a ocorrência de padrões texturais e espectrais que se repetem em diferentes escalas. A principal implicação desses resultados diz respeito às inferências sobre a dinâmica do Cerrado: a invariância escalar é uma característica marcante de sistemas que se desenvolvem longe do equilíbrio. Mais do que isso, é um grande indicativo de que o sistema pode apresentar criticalidade auto-organizada.Edição especia

    A moment based approach to the dynamical solution of the Kuramoto model

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    We examine the dynamics of the Kuramoto model with a new analytical approach. By defining an appropriate set of moments the dynamical equations can be exactly closed. We discuss some applications of the formalism like the existence of an effective Hamiltonian for the dynamics. We also show how this approach can be used to numerically investigate the dynamical behavior of the model without finite size effects.Comment: 6 pages, 5 figures, Revtex file, to appear in J. Phys.

    Assessment of complexity metrics applied to analysis of spectral patterns generated by aster sensor.

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    Landscape metrics are traditionally used in the analysis and search for spatial patterns in complex environmental systems through of establishing numeric relationships between different types of targets on Earth's surface. Under this perspective, remote sensing has had great importance as a tool for data generation, providing several levels of land use and occupancy information isonomically for large areas. For that purpose, remote sensing uses regular pixel matrices (Picture Element) with associated quantitative values (e.g. digital numbers, radiance, reflectance) which constitute a direct measurement of the variation of electromagnetic radiation (EMR) after interaction with the target. The variations in pixel values may be considered in terms of their textural patterns, regarding pixel neighborhood relationships, or spectral patterns, when EMR variations are considered along different wavelengths for a same pixel. Thus, the objective of this work was to assess the results of spectral measurements to different area extensions in images taken by the ASTER sensor, which operates with 9 bands within the visible to shortwave infrared region (0.556 to 2.400 µm) and has a spatial resolution of 15 m. For this purpose, cerrado phytophysiognomies in two hillsides at Jataí Ecological Station, in the city of Luiz Antônio, northeast portion of the state of São Paulo, Brazil, were considered reference targets, and encompassed to its greatest extent the cerradão domain and also "campo sujo" and "cerrado strictu sensu" physiognomies. The metrics used for spectral analyses are based on information entropy: measure (SDL), in which most complexity values are associated to more disorderly patterns; and measure, LMC, which is represent by a convex entropy of function that attributes greater complexity values to patterns located in an intermediate zone between order and disorder. These measures was applied to values extracted from spectral response curve generated by a wavelength X reflectance graphic which represented the target's behavior in different bands of the electromagnetic spectrum. In this work, was used two bands (8 and 9) that emphasize important components of cerrado phytophysiognomies, as lignin and water cell. For each hillside, was analysed three positions: base, medium and top, and each of these position, two spatial scales (150x150m and 75x75m). The results shows that, when taken alone, any measure presented a consistent behavior when compared of different spatial scales and bands used. However, both measures show identical behavior to attribute greater and lesser values of complexity to different positions and spatial scale at the same hillside. This results appoint that its can be used in combined as complementary measures, demonstrating in case LMC measure ? heterogeneity degrees of spectral patterns analysed and, from SDL measure, your respective location along of continuum that have in your extremes, one side, more ordered condition (therefore, more homogeneous) and, in the other extremity, more disordered conditions

    Self-control in Sparsely Coded Networks

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    A complete self-control mechanism is proposed in the dynamics of neural networks through the introduction of a time-dependent threshold, determined in function of both the noise and the pattern activity in the network. Especially for sparsely coded models this mechanism is shown to considerably improve the storage capacity, the basins of attraction and the mutual information content of the network.Comment: 4 pages, 6 Postscript figure

    HST Imaging of the BL Lacertae Object OJ 287

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    Hubble Space Telescope WFPC-2 I-band (F814W) images of the BL Lacertae object OJ 287 and the surrounding field are presented. We find evidence of associated extended nebulosity near OJ 287, as well as a small nebulosity to the West, which may be spatially coincident with the position of previously observed radio emission. The brightness of a host galaxy is difficult to determine due to the brightness of the active nucleus, but it lies in the range -21.5 > M_R > -23.1 (H_0 = 100 km s^{-1} Mpc^{-1}, q_0 = 0). No evidence is seen for the previously reported optical ``jet'' at position angle 220 degrees to a surface brightness limit of I = 24.3 mag arcsec^{-2}. There are several resolved and unresolved objects within 17'' of OJ~287 in the field to limits of I=25 (point source 5\sigma detections). The magnitudes and relative positions of these objects are reported. An offset in the centroid position between the OJ 287 point source and the underlying nebulosity reported by Wurtz, Stocke and Yee is confirmed and measured to be about 0.4 (1.2h^{-1} kpc at the redshift of OJ~287). This offset is tentatively interpreted as evidence for recent merger activity rather than a sign of gravitational microlensing.Comment: To appear in ApJ Letters, 3 jpg figure

    New Route for Valorization of Oil Mill Wastes: Isolation of Humic-Like Substances to be Employed in Solar-Driven Processes for Pollutants Removal

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    The valorization of olive oil mill solid wastes (OMW) has been addressed by considering it as a possible source of humic-like substances (HLSs), to be used as auxiliary substances for photo-Fenton, employing caffeine as a target pollutant to test the efficiency of this approach. The OMW-HLS isolation encompassed the OMW basic hydrolysis, followed by ultrafiltration and drying. OMW-HLS structural features have been investigated by means of laser light scattering, fluorescence, size exclusion chromatography, and thermogravimetric analysis; moreover, the capability of OMW-HLS to generate reactive species under irradiation has been investigated using spin-trap electronic paramagnetic resonance. The caffeine degradation by means of photo-Fenton process driven at pH = 5 was significantly increased by the addition of 10 mg/L of OMW-HLS. Under the mechanistic point of view, it could be hypothesized that singlet oxygen is not playing a relevant role, whereas other oxidants (mainly OH• radicals) can be considered as the key species in promoting caffeine degradation

    Enhancement of Water Transport and Microstructural Changes Induced by High-Intesity Ultrasound Application on Orange Peel Drying

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    The main aim of this work was to evaluate the effect of high-intensity ultrasound (US) on the drying kinetics of orange peel as well as its influence on the microstructural changes induced during drying. Convective drying kinetics of orange peel slabs were carried out at a relative humidity of 26.5±0.9%, 40 °C and 1 m/s with (AIR+US) and without (AIR) ultrasound application. In order to identify the US effect on water transport, drying kinetics were analyzed by taking the diffusion theory into account. Fresh, AIR and AIR+US dried samples were analyzed using Cryo-Scanning Electron Microscopy. Results showed that the drying kinetics of orange peel were significantly improved by US application, which involved a significant (p<0.05) improvement of mass transfer coefficient and effective moisture diffusivity. The effects on mass transfer properties were confirmed with microstructural observations. In the cuticle surface of flavedo, the pores were obstructed by the spread of the waxy components, this fact evidencing US effects on the air solid interfaces. Furthermore, the cells of the albedo were disrupted by US, as it created large intercellular air spaces facilitating water transfer through the tissue.The authors would like to acknowledge the financial support of MICINN and CEE (European Regional Development Fund) from projects Ref. DPI2009-14549-C04-04, PSE-060000-2009-003, and FP6-2004-FOOD-23140 HIGHQ RTE.García Pérez, JV.; Ortuño Cases, C.; Puig Gómez, CA.; Cárcel Carrión, JA.; Pérez Munuera, IM. (2012). Enhancement of Water Transport and Microstructural Changes Induced by High-Intesity Ultrasound Application on Orange Peel Drying. Food and Bioprocess Technology. 5(6):2256-2265. https://doi.org/10.1007/s11947-011-0645-0S2256226556Alandes, L., Perez-Munuera, I., Llorca, E., Quiles, A., & Hernando, I. (2009). 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    The sodium transporter encoded by the HKT1;2 gene modulates sodium/potassium homeostasis in tomato shoots under salinity

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    [EN] Excessive soil salinity diminishes crop yield and quality. In a previous study in tomato, we identified two closely linked genes encoding HKT1-like transporters, HKT1;1 and HKT1;2, as candidate genes for a major quantitative trait locus (kc7.1) related to shoot Na+/K+ homeostasis - a major salt tolerance trait - using two populations of recombinant inbred lines (RILs). Here, we determine the effectiveness of these genes in conferring improved salt tolerance by using two near-isogenic lines (NILs) that were homozygous for either the Solanum lycopersicum allele (NIL17) or for the Solanum cheesmaniae allele (NIL14) at both HKT1 loci; transgenic lines derived from these NILs in which each HKT1;1 and HKT1;2 had been silenced by stable transformation were also used. Silencing of ScHKT1;2 and SlHKT1;2 altered the leaf Na+/K+ ratio and caused hypersensitivity to salinity in plants cultivated under transpiring conditions, whereas silencing SlHKT1;1/ScHKT1;1 had a lesser effect. These results indicate that HKT1;2 has the more significant role in Na+ homeostasis and salinity tolerance in tomato.We thank Dr Espen Granum for critically reading the manuscript, Maria Isabel Gaspar Vidal and Elena Sanchez Romero for technical assistance, the Instrumental Technical Service at EEZ-CSIC for DNA sequencing and ICP-OES mineral analysis and Michael O'Shea for proofreading the text. In addition, we thank Dr Ana P. Ortega who assisted in preliminary experiments. This work was supported by ERDF-cofinanced grants, AGL2010-17090 and AGL2013-41733-R (A.B.), AGL2015-64991-C3-3-R (V.M.) and AGL2014-56675-R (M.J.A.) from the Spanish "Ministerio de Economia, Industria y Competitividad'; CVI-7558, Proyecto de Excelencia, from Junta de Andalucia (A.B); and the Australian Research Council (ARC) for Centre of Excellence (CE14010008) and Future Fellowship (FT130100709) funding (M.G.). N.J-P. was supported by an FPI program BES-2011-046096 and her stay in M.G.'s lab by a short-stay EEBB-I-14-08682, both from the Spanish from "Ministerio de Economia Industria y Competitividad'. The authors have no conflict of interest to declare.Jaime-Perez, N.; Pineda Chaza, BJ.; García Sogo, B.; Atarés Huerta, A.; Athman, A.; Byrt, CS.; Olias, R.... (2017). The sodium transporter encoded by the HKT1;2 gene modulates sodium/potassium homeostasis in tomato shoots under salinity. Plant Cell & Environment. 40(5):658-671. https://doi.org/10.1111/pce.12883S65867140
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